Add per-session force send pvs override (#4781)

Robust.Server/GameStates/PvsOverrideSystem.cs

@@ -18,6 +18,7 @@ public sealed class PvsOverrideSystem : EntitySystem
     internal HashSet<EntityUid> GlobalOverride = new();
     internal HashSet<EntityUid> ForceSend = new();
     internal Dictionary<ICommonSession, HashSet<EntityUid>> SessionOverrides = new();
+    internal Dictionary<ICommonSession, HashSet<EntityUid>> SessionForceSend = new();
 
     public override void Initialize()
     {
@@ -35,6 +36,7 @@ public sealed class PvsOverrideSystem : EntitySystem
             return;
 
         SessionOverrides.Remove(ev.Session);
+        SessionForceSend.Remove(ev.Session);
     }
 
     public override void Shutdown()
@@ -61,6 +63,12 @@ public sealed class PvsOverrideSystem : EntitySystem
             if (set.Remove(uid) && set.Count == 0)
                 SessionOverrides.Remove(session);
         }
+
+        foreach (var (session, set) in SessionForceSend)
+        {
+            if (set.Remove(uid) && set.Count == 0)
+                SessionForceSend.Remove(session);
+        }
     }
 
     /// <summary>
@@ -88,7 +96,7 @@ public sealed class PvsOverrideSystem : EntitySystem
     /// </summary>
     /// <remarks>
     /// This differs from <see cref="AddGlobalOverride"/> as it does not send children, and will ignore a players usual
-    /// PVS budget. You generally shouldn't use this.
+    /// PVS budget. You generally shouldn't use this unless an entity absolutely always needs to be sent to all clients.
     /// </remarks>
     public void AddForceSend(EntityUid uid)
     {
@@ -103,6 +111,35 @@ public sealed class PvsOverrideSystem : EntitySystem
         // might as well just do that when the entity gets deleted anyways.
     }
 
+    /// <summary>
+    /// This causes an entity and all of its parents to always be sent to a player..
+    /// </summary>
+    /// <remarks>
+    /// This differs from <see cref="AddSessionOverride"/> as it does not send children, and will ignore a players usual
+    /// PVS budget. You generally shouldn't use this unless an entity absolutely always needs to be sent to a client.
+    /// </remarks>
+    public void AddForceSend(EntityUid uid, ICommonSession session)
+    {
+        if (SessionForceSend.GetOrNew(session).Add(uid))
+            _hasOverride.Add(uid);
+    }
+
+    /// <summary>
+    /// Removes an entity from a session's force send set.
+    /// </summary>
+    public void RemoveForceSend(EntityUid uid, ICommonSession session)
+    {
+        if (!SessionForceSend.TryGetValue(session, out var overrides))
+            return;
+
+        if (overrides.Remove(uid) && overrides.Count == 0)
+            SessionForceSend.Remove(session);
+
+        // Not bothering to clear _hasOverride, as we'd have to check all the other collections, and at that point we
+        // might as well just do that when the entity gets deleted anyways.
+    }
+
+
     /// <summary>
     /// Forces the entity, all of its parents, and all of its children to ignore normal PVS range limitations for a
     /// specific session.

Robust.Server/GameStates/PvsSystem.Overrides.cs

@@ -52,6 +52,14 @@ internal sealed partial class PvsSystem
         {
             RecursivelyAddOverride(session, uid, fromTick, addChildren: false);
         }
+
+        if (!_pvsOverride.SessionForceSend.TryGetValue(session.Session, out var sessionForce))
+            return;
+
+        foreach (var uid in sessionForce)
+        {
+            RecursivelyAddOverride(session, uid, fromTick, addChildren: false);
+        }
     }
 
     private void RaiseExpandEvent(PvsSession session, GameTick fromTick)

Robust.Server/GameStates/PvsSystem.cs

@@ -326,12 +326,12 @@ internal sealed partial class PvsSystem : EntitySystem
             session.Budget.EnterLimit = CVars.NetPVSEntityEnterBudget.DefaultValue;
         }
 
-        // Process all entities in visible PVS chunks
-        AddPvsChunks(session);
-
         // Process all PVS overrides.
         AddAllOverrides(session);
 
+        // Process all entities in visible PVS chunks
+        AddPvsChunks(session);
+
         VerifySessionData(session);
 
         var toSend = session.ToSend!;